toy 2x2 matrices

M = 2 1       C = 4 0        K = 6 0
    1 3           0 5            0 7

Total CPU time in seconds = 4.00000e-002 

first 4 eigenvalues close to 1.000000 are

ans =

  -0.6430 - 1.1972i
  -0.6430 + 1.1972i
  -1.5570 - 1.4576i
  -1.5570 + 1.4576i

SUGAR

matrix is ill conditioned, cond = 3.83224e+016

Total CPU time in seconds = 9.11000e-001 

first 4 eigenvalues close to 1.000000 are

ans =

  1.0e+004 *

  -0.0515 - 7.5903i
  -0.0515 + 7.5903i
  -8.3655          
   8.2762          


QEPAS

Total CPU time in seconds = 3.10000e-001 

first 4 eigenvalues close to 1.000000 are

ans =

  1.0e+004 *

  -0.0000 - 0.0126i
  -0.0000 + 0.0126i
  -0.0008 - 2.7279i
  -0.0008 + 2.7279i